Bibcode
Jahnke, Knud; Bongiorno, Angela; Brusa, Marcella; Capak, Peter; Cappelluti, Nico; Cisternas, Mauricio; Civano, Francesca; Colbert, James; Comastri, Andrea; Elvis, Martin; Hasinger, Günther; Ilbert, Olivier; Impey, Chris; Inskip, Katherine; Koekemoer, Anton M.; Lilly, Simon; Maier, Christian; Merloni, Andrea; Riechers, Dominik; Salvato, Mara; Schinnerer, Eva; Scoville, Nick Z.; Silverman, John; Taniguchi, Yoshi; Trump, Jonathan R.; Yan, Lin
Bibliographical reference
The Astrophysical Journal Letters, Volume 706, Issue 2, pp. L215-L220 (2009).
Advertised on:
12
2009
Citations
171
Refereed citations
160
Description
We constrain the ratio of black hole (BH) mass to total stellar mass of
type-1 active galactic nuclei (AGNs) in the COSMOS survey at 1 < z
< 2. For 10 AGNs at mean redshift z ~ 1.4 with both Hubble Space
Telescope (HST)/ACS and HST/NICMOS imaging data, we are able to compute
the total stellar mass M *,total, based on rest-frame
UV-to-optical host galaxy colors which constrain mass-to-light ratios.
All objects have virial M BH estimates available from the
COSMOS Magellan/IMACS and zCOSMOS surveys. We find within errors zero
difference between the M BH-M *,total relation at
z ~ 1.4 and the M BH-M *,bulge relation in the
local universe. Our interpretation is (1) if our objects were purely
bulge-dominated, the M BH-M *,bulge relation has
not evolved since z ~ 1.4. However, (2) since we have evidence for
substantial disk components, the bulges of massive galaxies (M
*,total = 11.1 ± 0.3 or log M BH ~ 8.3
± 0.2) must have grown over the last 9 Gyr predominantly by
redistribution of the disk into the bulge mass. Since all necessary
stellar mass exists in galaxies at z = 1.4, no star formation or
addition of external stellar material is required, but only a
redistribution, e.g., induced by minor and major merging or through disk
instabilities. Merging, in addition to redistributing mass in the
galaxy, will add both BH and stellar/bulge mass, but does not change the
overall final M BH/M *,bulge ratio. Since the
overall cosmic stellar and BH mass buildup trace each other tightly over
time, our scenario of bulge formation in massive galaxies is independent
of any strong BH feedback and means that the mechanism coupling BH and
bulge mass until the present is very indirect.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained
at the Space Telescope Science Institute, which is operated by AURA,
Inc., under NASA contract NAS 5-26555, the XMM-Newton telescope, an ESA
science mission with instruments and contributions directly funded by
ESA Member States and NASA, the European Southern Observatory under
Large Program 175.A-0839, the Magellan Telescope which is operated by
the Carnegie Observatories, and the Subaru Telescope, which is operated
by the National Astronomical Observatory of Japan.